1. Field
One or more embodiments described herein relate to an optical disk device.
2. Background
FIG. 1 is a diagram showing an optical pickup in an optical disk device. The optical disk device includes a light source, a number of optical elements, and a light-receiving element. The light source may be a laser diode (LD) which radiates a laser beam, and the optical elements may include an objective lens (OL), a collimator lens, a beam splitter, and a sensor lens used to focus a beam emitted from the LD on an optical disk. The light receiving element (e.g., a photodiode (PD)) converts a beam reflected from the optical disk into an electrical signal.
According to the background art, the locations of the photodetector and optical elements are determined based on a mechanical reference surface having a certain tolerance, or based on continuously varying servo signals or an RF signal. Once this determination is made, the locations of the PD and OL are fixed and no further adjustments can be made. Thus, if errors are made in determining or fixing the locations of the PD and OL, no corrective measures can be taken. The locations errors are considered highly undesirable because they can create distortions that prevent the pickup from recovering data from the disk during a read operation.